Golf course sand bunkers are typically formed by filling a hole or pit in the ground with light colored playing sand to a depth of 3 to 5 inches. Over time however the underlying soil that is sometimes dark in color or contains small rocks and other unwanted particles mixes with the playing sand and creates an unsightly surface. Additionally, rainwater causes erosion of the underlying soil and deformation of the sand bunker, leaching of dirt into the light colored sand, and instability of the walls, all of which are undesirable in a golf course sand bunker.
The prior art consists of several ways to address this unwanted erosion and instability, but the systems thus far developed have been costly, labor intensive to apply, and complex. In U.S. Pat. No. 5,746,546, Hubbs et. al. describe a soil stabilization system comprising a subgrade barrier that absorbs water that is designed to prevent moisture build-up in a golf course sand bunker. The system comprises a layer of particulate aggregate, fiber strands, and a series of water-activated adhesive particles that swell when water is absorbed in order to provide a path for moisture egress. This system is complicated and expensive due to the variety of components including specialized fibers, water absorbent adhesives, and the requirement to carefully place a layer of aggregate stone underneath the playing sand of the golf course sand bunkers. The complexity and expense of this system, combined with its sensitivity to damage during use makes this an undesirable solution to the problem to overcome the erosion and degradation of golf course sand bunkers.
In U.S. Pat. No. 8,062,143, Meersman describes a sand bunker having multiple porous layers consisting of a matrix of aggregate stone built up in successive layers of decreasing particle sizes and having “numerous voids” between the pieces of aggregate. However, this system fails to provide any erosion protection for steep walled bunkers owing to the difficulty of placing multiple layers of aggregate along steep walls often present in sand bunkers of the world's finest golf courses. Further disadvantages of this system are the excess labor and materials needed to form such a system, which often includes digging a very deep bunker as a starting point to allow room for the multiple layers aggregate. A further safety concern is created by this system which intentionally includes aggregate particles underlying the playing sand, which risks being contacting by golf clubs during play and can damage golf club heads and lead to dangerous flying particles of aggregate stone.
In US Pat. App. No. 2011/0111216, Bowers describes an article comprising Portland cement mixed with colloidal silica that is substantially free of alkali metal to form a non-thixotropic coating, employed to improve the durability of paving systems. However, this system fails to provide a rigid base structure that can be successfully employed in a golf course sand bunker and merely attempts to seal a rigid article with an expensive top layer that fails to provide necessary strength and flexibility to the underlying layer.
Therefore a need exists in the art for a durable, inexpensive system and method for improving the erosion resistance and durability of golf course sand bunkers.